Question

1. The following describes the transportation of a substance from the glomerulus into the Bowman’s space:

a. Filtration

b. Secretion

c. Reabsorption

d. B and C

e. All of the Above

2. The following is secreted during dehydration:

a. Erythropoietin

b. Antidiuretic Hormone

c. Aldosterone

d. B and C

e. All of the Above

3. Angiotensin converting enzyme leads to the production of the following:

a. Angiotensin I

b. Angiotensin II

c. Aldosterone

d. B and C

e. All of the Above

Answer 1

1. Filtration

• The glomerulus filters the blood and removes water, glucose, salts and waste urea from it.
• The blood is under high pressure at the start of the nephron, which aids the filtration of the blood.
• These waste substances all pass from the capillaries in the glomerulus into the Bowman's capsule
• Tubular secretion occurs at Proximal Convoluted Tubule and Distal Convoluted Tubule

• At proximal convoluted tubule, potassium is secreted by means of sodium-potassium pump, hydrogen ion is secreted by means of active transport and co-transport.
• Reabsorption takes place mainly in the proximal convoluted tubule of the nephron.
• Nearly all of the water, glucose, potassium, and amino acids lost during glomerular filtration reenter the blood from the renal tubules.
• Reabsorption occurs primarily by passive transfer based on a concentration gradient, moving from a high concentration in the proximal tubule to the lower concentration in the capillaries surrounding the tubule.

2. B & C

• Both antidiuretic hormone and aldosterone is secreted during dehydration
• The kidneys have a renin-angiotensin hormonal system that increases the production of the active form of the hormone angiotensin II, which helps stimulate thirst
• It also stimulates the release of the hormone aldosterone from the adrenal glands.
• Aldosterone increases the reabsorption of sodium in the distal tubules of the nephrons and water follows this reabsorbed sodium back into the blood.
• The hypothalamus of a dehydrated person also releases antidiuretic hormone through the posterior pituitary gland.
• Antidiuretic hormone signals the kidneys to recover water from urine, effectively diluting the blood plasma

3. B & C

• Angiotensin II and aldosterone produced by angiotensin converting enzymes.
• Angiotensin-converting enzymes then convert angiotensin I to its physiologically active form, angiotensin II.
• Angiotensin II causes contraction of the muscles surrounding blood vessels, effectively narrowing vessels and increasing blood pressure.
• It also stimulates the release of aldosterone, which stimulates water and sodium reabsorption, thereby, increasing blood volume and blood pressure.